The present invention relates to a laryngeal mask airway device with a fiber optic assembly. More specifically, the present invention relates to an intutbating laryngeal mask airway device with a fiber optic assembly.
The laryngeal mask airway device is a well known device that is useful for establishing airways in unconscious patients. U.S. Pat. No. 4,509,514 is one of the many publications that describe laryngeal mask airway devices. Such devices have been in use for many years and offer an alternative to the older, even better known, endotracheal tube. For at least seventy years, endotracheal tubes comprising a long slender tube with an inflatable balloon disposed at the tube's distal end have been used for establishing airways in unconscious patients. In operation, the endotracheal tube's distal end is inserted through the mouth of the patient, past the patient's laryngeal inlet (or glottic opening), and into the patient's trachea. Once so positioned, the balloon is inflated so as to form a seal with the interior lining of the trachea. After this seal is established, positive pressure may be applied to the tube's proximal end to ventilate the patient's lungs. Also, the seal between the balloon and the inner lining of the trachea protects the lungs from aspiration (e.g., the seal prevents material regurgitated from the stomach from being aspirated into the patient's lungs).
Although they have been enormously successful, endotracheal tubes suffer from several major disadvantages. The principal disadvantage of the endotracheal tube relates to the difficulty of properly inserting the tube. Inserting an endotracheal tube into a patient is a procedure that requires a high degree of skill. Also, even for skilled practitioners, insertion of an endotracheal tube is sometimes difficult or not possible. In many instances, the difficulty of inserting endotracheal tubes has tragically led to the death of a patient because it was not possible to establish an airway in the patient with sufficient rapidity. Also, inserting an endotracheal tube normally requires manipulations of the patient's head and neck and further requires the patient's jaw to be forcibly opened widely. These necessary manipulations make it difficult, or undesirable, to insert an endotracheal tube into a patient who may be suffering from a neck injury.
In contrast to the endotracheal tube, it is relatively easy to insert a laryngeal mask airway device into a patient and thereby establish an airway. Also, the laryngeal mask airway device is a “forgiving” device in that even if it is inserted improperly, it still tends to establish an airway. Accordingly, the laryngeal mask airway device is often thought of as a “life saving” device. Also, the laryngeal mask airway device may be inserted with only relatively minor manipulations of the patient's head, neck, and jaw. Further, the laryngeal mask airway device provides for ventilation of the patient's lungs without requiring contact with the sensitive inner lining of the trachea and the size of the airway established is typically significantly larger than the size of the airway established with an endotracheal tube. Also, the laryngeal mask airway device does not interfere with coughing to the same extent as endotracheal tubes. Largely due to these advantages, the laryngeal mask airway device has enjoyed increasing popularity in recent years.
U.S. Pat. Nos. 5,303,697 and 6,079,409 describe examples of a type of prior art device that may be referred to as an “intubating laryngeal mask airway device.” The intubating device is useful for facilitating insertion of an endotracheal tube. After an intubating laryngeal mask airway device has been located in the patient, the device can act as a guide for a subsequently inserted endotracheal tube. Use of the laryngeal mask airway device in this fashion facilitates what is commonly known as “blind insertion” of the endotracheal tube. Only minor movements of the patient's head, neck, and jaw are required to insert the intubating laryngeal mask airway device, and once the device has been located in the patient, the endotracheal tube may be inserted with virtually no additional movements of the patient. This stands in contrast to the relatively large motions of the patient's head, neck, and jaw that would be required if the endotracheal tube were inserted without the assistance of the intubating laryngeal mask airway device.
One popular form of intubating laryngeal mask airway device has been marketed commercially for many yeas as the “Fastrach” by the Laryngeal Mask Company of Cyprus. FIG. 1A shows a view of the anterior side of a prior art Fastrach device 100. FIG. 1B shows a sectional view of device 100 taken in the direction of the arrows 1B—1B as shown in FIG. 1A.
Device 100 includes a rigid steel airway tube 110, a silicone mask portion 130, a rigid steel handle 180, and an inflation line 190. The handle 180 is attached to airway tube 110 near a proximal end 112 of the tube. Mask portion 130 is attached to airway tube 110 at a distal end 114 of the tube. Mask portion 130 includes a dome shaped backplate 132 and an inflatable cuff 134. Mask portion 130 also includes an epiglottis elevator bar 150. One end 152 of bar 150 is attached to the backplate 132. The other end 154 of the bar 150 is “free floating”, or not attached to any other portion of the device. The bar 150 is in effect hinged to the rest of the mask portion. FIGS. 1A and 1B show bar 150 in its resting position (i.e., the position assumed by the bar 150 when no external forces are acting on the bar 150).
In operation, cuff 134 is deflated, and the mask portion is then inserted through the patient's mouth into the patient's pharynx, while the proximal end 112 of the airway tube and the handle 180 remain outside of the patient's mouth. The handle 180 may be used for manipulating the device. The cuff 134 is then inflated to form a seal around the patient's glottic opening. After the device 100 is so positioned, a distal opening 117 of the device (shown in FIG. 1A) is aligned with the patient's glottic opening and the device provides a sealed airway extending from the proximal end 112 of airway tube 110 to the patient's trachea. When the epiglottis elevator bar 150 is in the resting position shown in FIGS. 1A and 1B, the bar 150 prevents the patient's epiglottis from falling into the bowl shape defined by the inflated cuff and backplate and consequently prevents the epiglottis from blocking the airway passage provided by the device. FIG. 1C shows an endotracheal tube 195 being inserted through device 100. The distal end 196 of the endotracheal tube 195 is inserted into the proximal end 112 of the airway tube and the endotracheal tube 195 is then advanced until the distal end 196 reaches and then passes through the mask portion 130. As shown, as the distal end 196 of the endotracheal tube 195 passes through the mask portion, it moves the distal end (or “free” end) 154 of bar 150 out of the resting position.
As shown in FIG. 1B, the airway tube 110 defines a curved region that extends from a proximal ray 116 to a distal ray 118, the rays 116, 118 meeting at a center of curvature C. As shown in FIGS. 1B and 1C, the backplate 132 defines a ramp 140. The curvature of the airway tube 110 and the ramp 140 make blind insertion of the endotracheal tube possible. That is, when device 100 is inserted in a patient, the curve of the airway tube and the ramp insure that the distal tip of a subsequently inserted endotracheal tube will be aligned with the trachea when it passes through the distal opening of device 100. The angle theta (θ) defined by rays 116, 118 is approximately one hundred twenty degrees. The ramp 140 adds about seventeen additional degrees to this curve such that an endotracheal tube inserted through the device curves through about one hundred thirty seven degrees.
The Fastrach is a reusable device and may be sterilized (and reused) many times before becoming too worn for reuse. Although the Fastrach has performed very well, there remains a need for improved intubating laryngeal mask airway devices.